(1) welcome, (2) you'd make it a lot easier for us to help if you'd provide a minimal example document that shows us what you are doing.
– daleifFeb 9 '16 at 18:12

your latex is too old (ltluatex is distributed as part of the base latex distribution since October 2015 release)
– David CarlisleFeb 9 '16 at 18:34

In case someone stumbles upon this: A minimal working example would have been 4 lines: Some document class line, \usepackage{titlesec}, \begin{document} \end{document}.
– infamouswhiteknightFeb 9 '16 at 20:32

4

I'm voting to close this question as off-topic because the issue was due to outdated software
– egregFeb 9 '16 at 20:50